I think the "modesty" issue had more to do with upended women showing too much calf.

The old official judo uniform for women had "pegged" pants bottoms to prevent the unseemly display of the nethermost leg region. See >http://ejmas.com/jalt/jaltart_svinth_0201.htm< pic of Ayako Akutagawa, towards the bottom of the page. Also notice the white stripe on her black belt which denoted her rank in Joshi Judo.

I'm guessing that the exposed calf of a man is less disturbing to women.

Fukuda Sensei's book, "Born for the Mat" is a fascinating look at woman's Judo. She's still alive and is now a Kodakan Judo 9th Dan. The old pictures have some great beehive hairdos.